Declarations;
 Ethics approval and consent to participate : Ethical approval for the use of these animals was granted by the Animal Care and Use, Research Ethics Committee (ACUREC), University of Ibadan, Nigeria, ethical code number UIACUREC/17/0023.
 Consent for publication : Not Applicable
Data Accessibility statement : The datasets used and/or analyzed during the current study will be deposited in Dryad and Figshare upon acceptance for publication.
 Competing interests : There are no competing interests
 Funding statements – This research did not receive any grant from funding agencies in the public, commercial, or not-for-profit sectors.
 Authors’ contributions : SOM conceptualized, wrote and analyzed result of this manuscript, IOO donated the specimen used for the study, AA proofread and contributed some of the skull samples from another location.
 Acknowledgments – The authors acknowledge the technical staff and the curators of the skull museums in the Departments of Veterinary Anatomy, Federal University of Agriculture, Makurdi & University of Ibadan, and Department of Anatomy, University of Ilorin, for releasing these fragile bones for our investigations. – The authors declare no conflict of interests